This is the first I have heard about the oil cooler running through the radiator as well and possibly failing.

Maybe it is best to simply throw in a new radiator and call it good for another 100K. Hell, I dunno what the freak to do!

I have a new trans cooler to do the bypass but now I think I'll order a new radiator and replace it also before anything happens.

I just replaced the stock radiator on the wife's H3 due to the known issue with the top of the plastic tank cracking. Stock tank lasted 110K miles so hopefully the replacement will last just as long if not longer.

Double tap

"Yes I always use Dexcool" figure it's cheap insurance. against what ? not going another 100k?

Right there can be your problem, it is well known and documented this stuff can be corrosive!!!! The manufacture I used to work for used it for aprox 2 years in the equipment they sold. Well most everyone of those trucks ended up with either scaly build up in the engines & hose's to eaten apart rads!!!

It was even thought this crap was capable and responsible for the rash of 4.3 GM intake & gasket failures happening in the late 90s (along with every other GM engine in the time period with plastic intakes)

I would love to cut some of these failed rads apart, I would beat the farm the coolers were / are eaten thru buy dexcool.

I agree 100%. Dexcool ate the intake gasket on my gmc pick up and my blazer. My mechanic is dead against dexcool and flushes it out and replaces it with normal antifreeze. We have had it done on the wifes yukon. I need to get it done to the h2.

My h2 has external coolers on the rad. So I,m thinking the PO had it bypassed? For $150 I can't think of cheaper insurance to replace the rad. Compared to the thousands when it goes south.

On the todo list. Thanks for posting this.

My new radiator is going in Monday and then I can cross this off my list. At 100K now, should be good for as long as I own it...since I drive only about 5k a year.

Reading this thread makes me wanna replace some parts now. I have a 07 h2 with 70000 miles. So what exactly do I need to buy to fix this problem? I have a friend who is a good mechanic so it shouldn't be to hard to replace.

Start by flushing the coolant system if you have Dexcool in it...like I mentioned in my above post if I could examine these rads with the internal cooler failures I bet the we're eaten thru (corroded) which led to there failure...

So do you guys run normal green antifreeze through it then if your not running DexCool?

I would doubt by now that anyone has a factory warranty in effect but running regular antifreeze as opposed to DexCool I'm sure would void any warranty on those parts that may be affected by the antifreeze. Mine is an 06 but I only have about 60k on the odo so I haven't seen any issues. At the same time I do plan on using a separate tranny cooler at some point just to prevent any failures down the road.